Is Emma Hayes’ back three switch working at Chelsea?

The results and performances have hardly been perfect, but the underlying numbers are telling a slightly different story writes Jessy Parker Humphreys

In the 66th minute against Juventus, Emma Hayes withdrew Erin Cuthbert and brought on Jessie Fleming. The change seemed to kickstart Chelsea who, within three minutes of the substitution, scored what turned out to be the winning goal.

But the switch was not solely about personnel. With Erin Cuthbert having played as the right wing-back, the change saw Chelsea’s formation become a back four, with Jess Carter moving across to play right-back and Guro Reiten dropping deeper to play left-back.

“We changed something in the second half defensively, and I think it helped a lot,” said scorer Pernille Harder after the game. “I think we were stronger in defence in the second half, and we got the goal.”

Chelsea have been playing a back three ever since the second half of the Champions League final yet, given the shift during the Juventus game, is it possible that Hayes might be looking at moving away from the back three? And should she be?

Emma Hayes’ switch to a back three was primarily motivated by Chelsea’s vulnerabilities last season on both flanks. An injury to Maren Mjelde picked up during the Continental Cup final in March left Chelsea without a first choice right back, whilst Jonna Andersson’s performances in the Champions League led to her being dropped. Niamh Charles and Jess Carter instead became Chelsea’s fullbacks for the end of their Champions League run.

Chelsea were exposed defensively, particularly in the Champions League, where they won less defensive duels (59.6% compared to 67.2% in all other competitions), conceded more shots on target (10.22 compared to 6.28), and faced a higher expected goals against (1.53 compared to 0.72).

Having been unable to bring in any fullbacks over the summer, Hayes turned to a back three.

	Back 3	Back 4
Goals	2.6	2.88
Expected goals	2.06	2.27
Shots	14.6	14.72
Goals conceded	0.9	0.56
Expected goals conceded	0.57	0.8
Shots against	2.7	2.31

On the face of it, it seems to have had the desired effect. Chelsea’s expected goals conceded has gone down even if their actual goals conceded has risen. Given the nature of some of the goals Chelsea have conceded this intuitively makes sense. Beth Mead’s strike for Arsenal and Tabea Wassmuth’s for Wolfsburg were both taken extremely well.

However, on the pitch, Chelsea’s defenders do not look settled. All three of Wolfsburg’s goals in their recent UWCL fixture came as a result of individual Chelsea errors. Whilst these might not seem systemic, they can suggest that players are not comfortable with what is going on around them, forcing them to make poor decisions.

Centre-back configuration (L to R)	Minutes played	% of available minutes
Carter – Eriksson – Bright	27	3%
Eriksson – Carter – Bright	526	65%
Eriksson – Bright – Carter	83	10%
Eriksson – Nouwen – Bright	73	9%
Eriksson – Carter – Nouwen	4	0.5%
Nouwen – Carter – Bright	90	11%
Eriksson – Ingle – Bright	3	0.4%

Data: WyScout

Hayes has tried a wide range of centre-back configurations but the Eriksson – Carter – Bright formation is the only one she has used on multiple occasions. Given Jess Carter had never played centre-back before this switch, it has been an odd selection, especially given that the full-back is playing as the middle of the three.

It is not a position that Carter seems to have particularly taken to. The goal conceded against Juventus was a perfect example.

As the ball comes to Lisa Boattin, Lina Hurtig is positioned just slightly in between Jess Carter and Millie Bright. In fact, Carter has just the phase before cleared the ball away before it reaches Hurtig.

But Carter allows Hurtig to drift in behind her, leaving Magda Eriksson to pick her up. Now there are two Chelsea central defenders picking up no one, whilst Barbra Bonansea has started her run ahead of Guro Reiten.

If Carter keeps track of Hurtig, Eriksson is able to turn and attempt to defend Bonansea’s run. But instead she is left responsible for Hurtig as Bonansea runs into the space left behind her to score. Carter is actually the first to turn to face Bonansea’s run but she is way too far over to do anything about it.

Hayes does have other options if she wants to stick to the back three. Aniek Nouwen, the 22-year-old Dutch defender, may have only made one start in the WSL but her experience as a starting centre-back for the Netherlands at the Olympics has shown she can perform in high-pressure games against talented opposition. Meanwhile, the imminent return of Maren Mjelde from injury might provide Hayes with a more experienced alternative. Mjelde regularly plays at centre-back for her country, and deputised there for Chelsea when Magda Eriksson was injured last season.

There is also some evidence that the back three is impacting Chelsea’s build-up play. Last season, Magda Eriksson was essential to the way Chelsea built up attacks. But this season, playing as the left-sided centre-back, it seems like her influence has declined. Her team rank (players who have played over 50% of minutes) has gone from 3rd to 6th for progressive carries p90 and from 3rd to 4th for progressive passes p90, with the absolute numbers dropping too. Chelsea have not struggled to create good chances – their expected goals total is 4.1 higher than any other side in the WSL – but it may give Hayes pause for thought.

Season	Touches p90	Passes p90	Prog Passes p90	Prog Carries p90
2020/21	90.3 (1)	68.6 (1)	7.07 (3)	6.49 (3)
2021/22	81.3 (2)	56.9 (3)	5.21 (4)	4.17 (6)

It seems unlikely that the back four switch against Juventus was an indication of a tactical reversion, given there has been no change to the situation which led to Hayes abandoning it in the first place. Instead it probably suggested that Hayes is looking to see her team embody a tactical flexibility that will allow them to switch between the two systems as and when is required. The underlying numbers in the back three do suggest it has gone some way to having the desired effect defensively, even if that has required reigning in some of Chelsea’s free-wheeling attacking style. The question will be whether it holds up as the intensity rises and the opposition teams improve.

You can follow Jessy on Twitter @Jessyjph